Obesity is a Major Risk Factor for Hospitalization in Community-Managed COVID-19 Pneumonia

Abstract

Objective: We aimed to investigate whether the stratification of outpatients with coronavirus disease 2019 (COVID-19) pneumonia by body mass index (BMI) can help predict hospitalization and other severe outcomes.

Patients and methods: We prospectively collected consecutive cases of community-managed COVID-19 pneumonia from March 1 to April 20, 2020, in the province of Bergamo and evaluated the association of overweight (25 kg/m² ≤ BMI <30 kg/m²) and obesity (≥30 kg/m²) with time to hospitalization (primary end point), low-flow domiciliary oxygen need, noninvasive mechanical ventilation, intubation, and death due to COVID-19 (secondary end points) in this cohort. We analyzed the primary end point using multivariable Cox models.

Results: Of 338 patients included, 133 (39.4%) were overweight and 77 (22.8%) were obese. Age at diagnosis was younger in obese patients compared with those overweight or with normal weight (P<.001), whereas diabetes, dyslipidemia, and heart diseases were differently distributed among BMI categories. Azithromycin, hydroxychloroquine, and prednisolone use were similar between BMI categories (P>.05). Overall, 105 (31.1%) patients were hospitalized, and time to hospitalization was significantly shorter for obese vs over- or normal-weight patients (P<.001). In the final multivariable analysis, obese patients were more likely to require hospitalization than nonobese patients (hazard ratio, 5.83; 95% CI, 3.91 to 8.71). Results were similar in multiple sensitivity analyses. Low-flow domiciliary oxygen need, hospitalization with noninvasive mechanical ventilation, intubation, and death were significantly associated with obesity (P<.001).

Conclusion: In patients with community-managed COVID-19 pneumonia, obesity is associated with a higher hospitalization risk and overall worse outcomes than for nonobese patients.

Figure 1

A, Association of body mass index (BMI) categories and hospitalization at the end of follow-up in the studied cohort of community-managed coronavirus disease 2019 (COVID-19) pneumonia. B, Time to hospitalization by BMI categories in the studied cohort of community-managed coronavirus disease 2019 pneumonia. Hospitalization rate in obese vs overweight and normal-weight patients was significantly increased at 10 days (65.8% vs 14.8% vs 17.3%; P<.0001), 30 days (75.0% vs 17.2% vs 17.3%; P<.001), and end of follow-up (75.3% vs 17.2% vs 18.8%; P<.0001).

Figure 2

Adjusted hazard ratios of hospitalization in the final multivariable analysis. Shown are hazard ratios with 95% CIs from the final multivariable Cox proportional hazards model (model 1 of the Supplemental Table), which includes obesity with the additional covariates of sex (male), hydroxychloroquine (HCQ) use, and prednisolone use.

Figure 3

Association of body mass index (BMI) categories and (A) low-flow oxygen (O₂) need, (B) hospitalization with noninvasive ventilation (NIV), and (C) intubation at the end of follow-up in the studied cohort of community-managed coronavirus disease 2019 (COVID-19) pneumonia. (D) Time to death by BMI categories in the studied cohort of community-managed COVID-19 pneumonia. Overall, low-flow O₂ need, NIV, and intubation at the end of follow-up were significantly higher in obese compared with nonobese patients. Survival rates in obese vs nonobese patients were nonsignificantly different at 10 days (98.7% vs 99.6%; P>.05), while they were significantly different at 30 days (95.3% vs 98.5%; P<.05) and end of follow-up (93.6% vs 98.5%; P<.05). ICU, intensive care unit.